HOW DO YOU CHANGE SPARK PLUGS + IGNITION

I need to change my spark plugs+ignition wires and I am not sure how to do this? The 3 plugs and ignition wires on the backside of the motor are really hard to get to. Do you need to take part of the motor off or what? The reason I am changing them is because whenever I drive up a hill or try to increase my speed show and steady, the car starts hesitating and it feels like a plug is misfiring or it is not getting enough gas. Then it goes away if I step on the excelerator pretty good.